init(PMContext context)
Initializes the persistence manager. The persistence manager is
permanently bound to the given context, and any required external
resources are acquired.

An appropriate exception is thrown if the persistence manager
initialization fails for whatever reason. In this case the
state of the persistence manager is undefined and the instance
should be discarded.
Initializes the internal structures of this abstract persistence manager.

void

setDerbyStorageInitialPages(String derbyStorageInitialPages)
The on-disk size of a Derby table grows by one page at a time until eight
pages of user data (or nine pages of total disk use, one is used for
overhead) have been allocated.

setDerbyStoragePageReservedSpace(String derbyStoragePageReservedSpace)
Defines the percentage of space reserved for updates on an on-disk
database page for tables only (not indexes); indicates the percentage of
space to keep free on a page when inserting.

void

setDerbyStoragePageSize(String derbyStoragePageSize)
Defines the page size, in bytes, for on-disk database pages for tables or
indexes used during table or index creation.

setDerbyStorageInitialPages

The on-disk size of a Derby table grows by one page at a time until eight
pages of user data (or nine pages of total disk use, one is used for
overhead) have been allocated. Then it will grow by eight pages at a time
if possible.

A Derby table or index can be created with a number of pages already
pre-allocated. To do so, specify the property prior to the CREATE TABLE
or CREATE INDEX statement.

Define the number of user pages the table or index is to be created with.
The purpose of this property is to preallocate a table or index of
reasonable size if the user expects that a large amount of data will be
inserted into the table or index. A table or index that has the
pre-allocated pages will enjoy a small performance improvement over a
table or index that has no pre-allocated pages when the data are loaded.

The total desired size of the table or index should be

(1+derby.storage.initialPages) * derby.storage.pageSize bytes.

When you create a table or an index after setting this property, Derby
attempts to preallocate the requested number of user pages. However, the
operations do not fail even if they are unable to preallocate the
requested number of pages, as long as they allocate at least one page.

setDerbyStorageMinimumRecordSize

Indicates the minimum user row size in bytes for on-disk database pages
for tables when you are creating a table. This property ensures that
there is enough room for a row to grow on a page when updated without
having to overflow. This is generally most useful for VARCHAR and
VARCHAR FOR BIT DATA data types and for tables that are updated a lot,
in which the rows start small and grow due to updates. Reserving the
space at the time of insertion minimizes row overflow due to updates,
but it can result in wasted space. Set the property prior to issuing the
CREATE TABLE statement.

When increasing the size of the page cache, you typically have to allow
more memory for the Java heap when starting the embedding application
(taking into consideration, of course, the memory needs of the embedding
application as well). For example, using the default page size of 4K, a
page cache size of 2000 pages will require at least 8 MB of memory (and
probably more, given the overhead).

The minimum value is 40 pages. If you specify a lower value, Derby uses
the default value.

Default is 1024 (which gives about 16mb memory usage given
the default of 16384 as page size).

setDerbyStoragePageReservedSpace

Defines the percentage of space reserved for updates on an on-disk
database page for tables only (not indexes); indicates the percentage of
space to keep free on a page when inserting. Leaving reserved space on a
page can minimize row overflow (and the associated performance hit)
during updates. Once a page has been filled up to the reserved-space
threshold, no new rows are allowed on the page. This reserved space is
used only for rows that increase in size when updated, not for new
inserts. Set this property prior to issuing the CREATE TABLE statement.

Regardless of the value of derby.storage.pageReservedSpace, an empty page
always accepts at least one row.

Default is 20%

Parameters:

derbyStoragePageReservedSpace - the page reserved space

getDerbyStoragePageSize

setDerbyStoragePageSize

Defines the page size, in bytes, for on-disk database pages for tables or
indexes used during table or index creation. Page size can only be one
the following values: 4096, 8192, 16384, or 32768. Set this property
prior to issuing the CREATE TABLE or CREATE INDEX statement. This value
will be used for the lifetime of the newly created conglomerates.

init

Initializes the persistence manager. The persistence manager is
permanently bound to the given context, and any required external
resources are acquired.

An appropriate exception is thrown if the persistence manager
initialization fails for whatever reason. In this case the
state of the persistence manager is undefined and the instance
should be discarded.
Initializes the internal structures of this abstract persistence manager.